Lecture_11_DulaiS09_Energy

Lecture_11_DulaiS09_Energy - Lecture 11 Agenda: The ground...

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1 Lecture 11 Agenda: The ground rules of metabolism. 4. How do living systems concentrate and use energy? 3. What are the 1 st and 2 nd laws of thermodynamics and what do they imply about living systems?! 2. What is metabolism? What is its relationship to energy? 1. Cell Transport? How are they similar? How do they differ?
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2 Plasma membrane cytoplasm Exocytosis Cells use special mechanisms for importing or exporting large cargos or amounts of material Figure 5.16a Extracellular environment
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3 Exocytosis and endocytosis continually replace and withdraw patches of plasma membrane lysosome Golgi body clathrin Plasma membrane is constantly renewed Digestive organelle Movie
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4 Summary – Key Concepts •The plasma membrane is a fluid mosaic of many compounds •The membrane is selectively permeable •Cells use five principal mechanisms for transporting material across the membrane •In passive transport , the proteins provide a transmembrane channel, move compounds down a concentration gradient active transport , the proteins use ATP to pump the solute up a concentration gradient Exocytosis is used to export large cargos Endocytosis can be either selective (receptor-mediated) or less selective (bulk-phase)
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5 Ground rules of metabolism Lecture 8 Chapter 6
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6 Energy is the capacity to do work ; energy comes in many interconvertible forms Gravitational Energy Kinetic Energy Mechanical Energy Light (Electromagnetic) Energy Nuclear Energy Chemical Energy
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7 First Law of Thermodynamics: deals with energy quantity • The total amount of energy in the universe remains constant • Energy can undergo conversions from one form to another, but it cannot be created or destroyed Nuclear energy (holds protons, neutrons together) Electromagnetic energy (light + heat; lots of it!) Electromagnetic energy (light) Chemical energy (glucose, ATP)
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8 What Can Cells Do with Energy? • Energy inputs become coupled to energy-requiring processes • Cells use energy for: – Chemical work – Mechanical work – Electrochemical work
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9 One-Way Flow of Energy •O u r Sun is life’s primary energy source • Producers trap energy from the sun and convert it into chemical bond energy •A l l organisms use the energy stored in the bonds of organic compounds to do work
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10 • No energy conversion is ever 100 percent efficient - never • Energy flows from high-energy, very usable forms to less usable, lower energy forms – This is the reason why we have diffusion – The energy in our Sun diffuses out in to the Universe – The concentrated organization of your body dismantles when you die!
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Lecture_11_DulaiS09_Energy - Lecture 11 Agenda: The ground...

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